Bisoxalic acid diamides

ABSTRACT

NEW BISOXALIC ACID DIAMIDES ARE STABILISERS FOR ORGANIC MATERIALS. THEY ARE PREPARED BY REACTING AN OXALIC ACID MONOAMIDE OR THE CHLORIDE OR AN ESTER THEREOF WITH AN ALKYLENDIAMINE.

United States Patent Ice Q132 3:

The above characterised compounds can be produced 3,706,798 by process analogous to processes known per se. BISOXALIC ACID DIAMIDES Basically, a compound of the formula Max Dunnenberger, Frenkendorf, Basel-Land, and Hans Rudolf Biland, Gelterkinden, Basel-Land, Switzerland, (0113):? assignors to Ciba-Geigy AG, Basel, Switzerland 0 N0 Drawing. Filed Apr. 12, 1971, Ser. No. 133,377 GX Int. Cl. C07c 103/32 US. Cl. 260559 A Claims 011 l;

10 is thereby reacted with a compound of the formula ABSTRACT OF THE DISCLOSURE X' --X' New bisoxalic acid diamides are stabilisers for organic X and X represent either -NH or materials They are prepared by reacting an oxalic acid monoamide or the chloride or an ester thereof with an lk l i i wherein Y stands for Cl, -OH or an alkoxy group having 1 to 12 carbon atoms. R has the above given mean- DETAILED DESCRIPTION ing. X and X must be different in the two reactants. This means that one mole of a compound of the formula It is already known that a large number of bisoxalic acid diamides can be used as ultraviolet absorbers. (6) f n It has now been found by a further study of this field Y( JO-NH-RHN- J- i-Y that a selected group of new bisoxalic acid diamides possess, as anti-oxidants, outstanding properties which are lacking in compounds of very similar constitution.

These new 'bisoxalic acid diamides correspond to the wherein Y and R have the given meaning is reacted with 2 moles of 3,S-di-tert.butyl-4-hydroxy-aniline; or 1 mole of a diamine of the formula formula (7) NH;R-NH

C (01393 (H) i I? m HO NH-C-C-NH-R-NH-dJ-i-HN OH (011m (CH1)! wherein R has the given meaning is reacted with 2 moles wherein R represents an alkylene radical having 5 to 18 f a compound of h formula carbon atoms.

The alkylene radical R in Formula 1 can be branched (8) (CHMC O O or, preferably, unbranched. HO ll l Of particular practical interest, especially as anti-oxidants for poly-a-olefins, are bisoxalic acid diamides of CH g the formula 3):.

wherein Y has the given meaning.

CH C C CH 3):: I g I I a)! H0 -NH-CCNH CHz NH- '3-ti-HN OH 08 (CH2):

wherein n represents a whole number from 6 to 10. In Formula 6 the symbol Y hereby represents pref- Preferred compounds within the scope of Formula 2 erably chlorine, whilst in Formula (8) it preferably stands correspond to the formula for an alkoxy group having 1 to 12 carbon atoms.

CH C 0 CH m a)a I s)a wherein. m represents a whole number from 6 to 8.

action is performed, depending on the reactivity of the functional group to be reacted, at temperatures between and 250 C. in a solvent inert to the reactants, or in the melt, optionally in the presence of a condensation catalyst. Preferred condensation catalysts are tertiary amines such as triethanolamine and pyridine, also acids such as boric acid and p-toluenesulphonic acid.

The amount of catalyst to be used is, in general, 0 to percent by weight, relative to the total weight of the reactants. Preferably, the reaction is performed in a solvent at a temperature of 30 to 80 C. Suitable solvents are, for example, aromatic hydrocarbons, or aromatic halogenated hydrocarbons such as benzene, toluene, p-

Example 1 t An amount of 6.4 g. of compound of the formula HO -NH( J-OCzHs a)a( J (produced by reaction of 1-amino-3,5-di-tert.butyl-4- hydroxybenzene with oxalic acid monoethyl ester chloride in benzene with pyridine as the HCl-acceptor; melting point: 139 to 140 C.), is refluxed, with stirring, in 60 cubic centimetres of ethanol with 1.2 g. of 1,6-diaminohexane for 3 hours. The reaction mixture is subsequently cymol, chlorobenzene, diand trichlorobenzene, alcohols cooled to 10 C., whereby the product of the formula (G Ha) a C or ethers, such as methanol, ethanol, ethylene glycol, diethylene glycol, triethylene glycol, glycerin, ethylene glycol monomethyl ether, diethylene glycol diethyl ether, and dioxane, or also methylene chloride.

The compound of Formula 8 wherein Y represent alkoxy is produced, for example, by reaction of l-amino- 3,S-di-tert.butyl-4-hydroxybenzene with oxalic acid monoalkylester-chloride in benzene with pyridine 'as HClacceptor.

The described new compounds constitute valuable antioxidants, i.e. they are suitable for the stabilisation of organic materials to oxidative decomposition, by which is meant, in particular, thermally accelerated oxidations. Materials which can be protected are: homo-and copolymerisates made from ethylenically unsaturated compounds such as vinyl chloride, vinylidene chloride, styrene, butadiene, isoprene, ethylene, propylene, acrylicand methacrylic acid derivatives, e.g. acrylic acid alkyl ester, acrylic acid amides, and acrylonitrile; polamides, e.g. made from e-caprolactam, or from adipic acid and a diamine; polyesters such as terephthalic acid glycol polyesters; natural and synthetic rubbers; lubricating oils;- benzines; vegetable and animal oils and fats; waxes; cellulose and cellulose derivatives such as celluloseester.

To be specially emphasised is the excellent anti-oxidant effect of the above defined compounds in the case of polymerisate synthetic materials, particularly poly-u-olefins such as polypropylene.

Sufficient for a good anti-oxidant effect is, in general, an amount of 0.01 to 5%, preferably 0.1 to 2% of the compounds according to the invention, relative to the substrate to be protected. The anti-oxidants can be worked on their own into the materials to be protected, or together with other additives such as softeners, pigments, protective agents against light-rays (UV-absorbers), secondary anti-oxidants, optical brighteners, with or without the aid of solvents.

The good stabilising effect of the new compounds is shown, e.g. under accelerated ageing conditions at temperatures above 100 C. A polypropylene subjected to these conditions which contains an anti-oxidant does not show signs of a discolouration, or of the material becoming tender, until after a very much longer time than the time required for this to occur in the case of a polypropylene containing no stabiliser.

Where not otherwise stated in the following examples, the term parts denotes parts by weight, and the term percent denotes percent by Weight. The melting points of the new mp unds a e not corrected.

ienna precipitatesin the form of colourless crystals. Yield: approximately 7g. After recrystallisation three times from ethanol, the analytical product melts at 230 to 231 C.

- Thefollowing compounds of Formula 1 are produced in an analogous manner:

A mixture of parts ofvstabiliser-free polypropylene (Profax 6501, Hercules Powder) and 0.2 part of a compound according to the below given table is processed on a calendering machine at 170 C. into a soft sheet, and this subsequently pressed at 230 C., and under a pressure of 40 kg./cm. to form a plate of '1 mm. "thickness. The thus obtained plates are subjected at C. (air, normal-pressure) to an accelerated oxygen ageing treatment. The time passing before the appearance of thefirst cracks detectable with the eye isa' measure of the antioxidativ effect of the added compound. i

TABLE I Time in hours until Added compound: cracks form at 140 C.

Compounds according to the invention Compound of Time in hours until the formula: v H cracks form at 140 C. (10 2250 (11 2250 (12 20 00 (14) 1830,

5 6 What is claimed is: l. A bisoxalic acid diamide of the formula wherein R represents an alkylene radical having 5 to 18 carbon atoms.

2. A bisoxazolic acid diamide according to claim 1 of 10 the formula wherein n represents a whole number form 6 to 10.

3. A bisoxalic acid diamide according to claim 1 of the formula 20 (CH3)3C C(CHB)! F i I i HO -NH c-c NH{cH2)-NH-c-c-HN oH ll ah w ah 4. A bisoxazolic acid diamide according to claim 1 of the formula References Cited UNITED STATES PATENTS 3,256,284 1/1966 Rio 260--559 HENRY R. JILES, Primary Examiner H. I. MOATZ, Assistant Examiner US. Cl. X.R. 

